This invention relates generally to the field of drilling, completion, and repair operations on wells in an underwater environment.
Well interventions in subsea deepwater wells generally cost in excess of $200,000 per day (typically on the order of $10,000,000 per intervention) with operations usually being conducted by a floating deepwater drilling rig. Many operators are investigating the feasibility of utilizing purpose built well intervention vessels, but with anticipated operating costs in excess of $100,000 per day ($5,000,000 per intervention), costs are still too high for many reservoir management options to be economic. Reducing the cost of intervention would allow greater optimization of reservoir management with respect to both rate and ultimate recovery.
Accordingly, there is a need for an apparatus and operating procedure, which will allow reduction of costs associated with drilling, completion, and repair operations on wells in an underwater environment.
The subject invention provides an apparatus and a method for introducing tools into a subsea well or pipeline from a subsea location. The apparatus is an intervention system for servicing subsea wells or pipelines from a subsea location, comprising a tool delivery device, a reel to hold the tool delivery device, an injector head, a carousel tool caddy, a blow-out-preventer assembly, a power pack, a control pod, a test pump, and an open space frame. The system may be disconnected into two sections, allowing removal of the tool caddy, for replacement of tools at a remote location.
The subject invention also includes an improved method for introducing a tool into a subsea well or pipeline from a subsea location, comprising (for a well): (a) connecting a well intervention system to a subsea tree, wherein the well intervention system includes a reeled tool delivery device and a carousel tool caddy capable of holding one or more tools; (b) rotating the carousel tool caddy so that a selected tool is located over the well; (c) connecting a tool delivery device to the selected tool; and (d) introducing the selected tool into the well. The tools are used to conduct various intervention activities.